Its been more than 10 years since i've read it. Its about a highschool girl and her (mean) bodyguard. The author draws the male leads with jewelry, like rings on fingers. And in general, the leads had jewelry most of the time even in other stories
try looking through this tag:
https://www.mangago.zone/tag/bodyguard/?page=1
Yuhuuu we got new sex positions and stuff. That was refreshing